This is the seventh in a series of workshops for scientists and clinicians to share recent work in primary hyperoxaluria (PH) and oxalate-mediated disease to be held October 8-10, 2004 at Mayo Clinic in Rochester, Minnesota. The primary hyperoxalurias are rare, autosomal recessive disorders, with a community of scientists and clinicians dedicated to research and care for affected patients. The small size and diverse nature of this community of molecular geneticists, physiologists, protein chemists, epidemiologists, nephrologists, urologists, and transplant surgeons is such that focused workshops are essential to bring them together. Previous workshops have been marked by open discussion, rapid dissemination of new results, and successful stimulation of international collaboration. Sessions expressly designed for patients and their families are a novel addition to the 2004 Workshop. Objectives: a) Define the state of the art of the molecular basis of primary hyperoxaluria, causes of tissue injury associated with this disease, and review new approaches to treatment, b) Promote discussion between an international group of basic scientists and clinicians, thereby fostering scientific collaboration, c) Promote participation in the new international Registry for Inherited Calcium Urolithiasis, and d) Provide patients and their families direct and accurate information, interaction with experts in this disease, and a forum for peer support. Topics to be covered include recent advances in AGT genomics and the emerging role of genetic testing for predicting clinical course and guiding therapy, insights from PH registry data, mechanisms of oxalate injury of cells and tissues, molecular approaches to treatment, and promising new therapeutics. Patient and family sessions will focus on the cause of PH, genetic testing, treatments, and new areas of promising research. Recent crystallization of the AGT protein, and advances in the molecular genetics, diagnostic testing, and pharmacogenomics of PH make 2004 an exciting year for the 7th Workshop.